This invention relates generally to the transport of semi-trailers by rail.
Such intermodal transport has become increasingly important in urban areas where freight shippage requirements are high and there is a concurrent need to reduce semi-trailer traffic on busy expressways.
Many urban areas, citing increased road damage and traffic accidents, have introduced legislation which heavily taxes and regulates truck traffic. The transport of semi-trailers by rail has thus found widespread use in the freight shipping arts.
The loading, unloading and safe transport of semi-trailers by rail have posed significant problems with prior art systems.
U.S. Pat. No. 4,653,966 illustrates a system wherein a semi-trailer is driven onto a bogie. Such system requires a large truck turning area and a high degree of driver skill to accomplish the loading process. Further, various locking adjustments must be made after loading to secure the semi-trailer to the bogie. Such requirements, due to the time and labor costs involved, have been found to be unsatisfactory in the intermodal transport arts.
U.S. Pat. No. 4,574,707 illustrates the prior art use of lifting, apparently via crane, a semi-trailer onto a rail bogie for transport. Such system requires a very costly multiple spring-type design and still does not achieve the desired securing function for the load to be carried.
U.S. Pat. No. 2,992,621 is an older design which generally illustrates the use of turntables in the railroad trailer transport arts.
In view of the known prior art systems, it is accordingly an object of the present invention to demonstrate a railway bogie which may be economically manufactured without the complexities inherent in prior art designs.
It is a further object of the invention to produce an intermodal transport system which may be efficiently used without the labor-intensive load securing requirements currently in use.
It is also an object of the invention to demonstrate a design wherein the longitudinal movement of a trailer is automatically restrained without the need for costly lock-down requirements of the prior art.
It is a still further object of the invention to provide a low-riding, close to the rail pivoting system which insures maximum stability and protection for the transported load.
These and other objects and advantages of the invention will be apparent to those of skill in the art from the description which follows.